U.S. patent application number 11/350859 was filed with the patent office on 2006-08-10 for method and apparatus for bead removal.
Invention is credited to Stephen Robert Bysouth.
Application Number | 20060177353 11/350859 |
Document ID | / |
Family ID | 36793724 |
Filed Date | 2006-08-10 |
United States Patent
Application |
20060177353 |
Kind Code |
A1 |
Bysouth; Stephen Robert |
August 10, 2006 |
Method and apparatus for bead removal
Abstract
The invention is a device and method for separating liquids from
solid particles in a laboratory. The device consists of a pipette
tip, which has holes or slots arranged radially around the axis of
the tip and the lower end of the tip, closed. The smallest
dimension of the hole or slit is smaller than the diameter of the
solid particles from which the liquid is to be separated. These
holes or slits are positioned towards the lower end of the tip such
that when plunged into a sample, they are below the level of the
phase to be extracted. The method comprises mounting the device on
a manual or robotic pipettor, plunging the tip into a mixture of
solid particles and liquid to be separated, aspirating the liquid
and removing the tip with the aspirated liquid, leaving the solid
particles behind in the original container.
Inventors: |
Bysouth; Stephen Robert;
(Houston, TX) |
Correspondence
Address: |
MILES & STOCKBRIDGE PC
1751 PINNACLE DRIVE
SUITE 500
MCLEAN
VA
22102-3833
US
|
Family ID: |
36793724 |
Appl. No.: |
11/350859 |
Filed: |
February 10, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60651224 |
Feb 10, 2005 |
|
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|
Current U.S.
Class: |
422/400 |
Current CPC
Class: |
B01L 2300/0681 20130101;
G01N 2035/00564 20130101; G01N 2035/00574 20130101; B01L 3/0275
20130101; G01N 35/10 20130101; B01L 2300/0858 20130101; B01J
2219/005 20130101; B01J 2219/00468 20130101; G01N 1/4077 20130101;
B01L 2200/0657 20130101; G01N 2035/1053 20130101 |
Class at
Publication: |
422/100 |
International
Class: |
B01L 3/02 20060101
B01L003/02 |
Claims
1. A device comprising: a tube, said tube comprising an upper end
having a first opening and a lower end, wherein said tube is
narrowed at said lower end to form a tip having a second opening;
an aspiration means, wherein said aspiration means is connectable
to said upper end of said tube; and at least one third opening(s),
wherein said third opening(s) are located on said lower end.
2. The device of claim one, wherein said third opening(s) are
radially located on said lower end.
3. The device of claim one, wherein said third opening(s) are round
or slits.
4. The device of claim one, wherein said device separates solid
particles from a liquid and wherein said third opening(s) are
smaller than said solid particles.
5. The device of claim one wherein said second opening is blocked
or screened.
6. The device of claim one wherein said third opening(s) are
located at least two millimeters from said second opening.
7. The device of claim one wherein the device is connectable to a
manual pipetting system.
8. The device of claim one wherein the device is connectable to an
automated pipetting system.
9. The device of claim one wherein said third opening(s) are
arranged radially around said second opening.
10. A method of bead transfer comprising: mounting a device on a
manual or robotic pipettor, said device comprising: a tube, said
tube comprising an upper end having a first opening and a lower
end, wherein said tube is narrowed at said lower end to form a tip
having a second opening; an aspiration means, wherein said
aspiration means is connectable to said upper end of said tube; and
at least one third opening(s), wherein said third opening(s) are
located on said lower end; plunging said tip into a mixture,
wherein said mixture comprises solid(s) and liquid(s), wherein said
solid(s) comprises solid particle(s); and aspirating said
liquid.
11. The method of claim ten further comprising: removing said
tip.
12. The method of claim ten, wherein said third tube opening(s) are
radially located on said lower end; and wherein said third tube
opening(s) are round or slits.
13. The method of claim ten, wherein said third tube opening(s) are
smaller than said solid particle(s)
14. The method of claim ten wherein said second opening is blocked
or screened.
15. The method of claim ten wherein said third opening(s) are
located at least four millimeters from said second opening.
16. The method of claim ten wherein the device is connectable to a
manual pipetting system.
17. The method of claim ten wherein the device is connectable to an
automated pipetting system.
18. The method of claim ten wherein said third opening(s) are
arranged radially around said second opening.
19. A device comprising: a tube, said tube comprising an upper end
having a first opening and a lower end, wherein said tube is
narrowed at said lower end to form a tip having a second opening,
wherein said second opening is blocked or screened; an aspiration
means, wherein said aspiration means is connectable to said upper
end of said tube; and at least one third opening(s), wherein said
third opening(s) are radially located on said lower end, and
wherein said third tube opening(s) are round or slits,
20. The device of claim 19, wherein said device separates solid
particles from a liquid and wherein said third opening(s) are
smaller than said solid particles.
Description
RELATED APPLICATION
[0001] This patent application claims priority to U.S. Provisional
application Ser. No. 60/651,224 filed Feb. 10, 2005, which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates generally to a device and method of
separating a liquid, emulsion or suspension from solid particles.
Specifically the present invention relates to a means to separate
solid particles used in comminution, milling, mixing and/or
homogenisation techniques from the material that has been
processed, especially in automated systems.
BACKGROUND OF THE INVENTION
[0003] Certain formulation techniques require the use of solid
particles or beads. After processing a material, such as a mixture
of chemicals, to produce a formulation using techniques that result
in a processed sample containing solid particles, a need was
identified to separate the solid particles from the formulation in
order to use, test or analyse the formulation. This was especially
challenging in an automated environment, such as a laboratory `High
Throughput` formulation preparation system, where the sample
quantity is often limited. Where the solid material is a magnetic
bead, electromagnetic techniques may be used to pull the beads from
the formulation. However, when using comminution techniques, it is
desirable to use non-magnetic ceramic beads as they minimally
contaminate the formulation during processing and improve the
processing time because of their hardness and density. Filtration
techniques are impractical because the sample size is limited and
present significant engineering challenges in an automated system,
in themselves.
[0004] Pipetting techniques are commonly available on laboratory
robotic systems and this technique was tried using standard
disposable pipette tips. However, when the bead size was at or
greater than the diameter of the entrance hole of the pipette tip,
the pipette became blocked by a bead and when the diameter of the
beads was less than the diameter of the entrance hole, the beads
entered the pipette such that in each of these cases, separation
was not possible. The invention described herein provides the
chemist with a means of successfully separating beads from a
formulation and makes possible the automation of this
technique.
SUMMARY OF THE INVENTION
[0005] The invention consists of a specially designed pipette tip
and methodology that allows the separation of solid particles or
beads from a liquid matrix.
[0006] The system enables chemists who produce samples using, for
example, wet milling techniques, to separate the solid particles or
beads from the processed sample, which can then be carried forward
to other steps in their workflow. In addition to providing a means
to manually separate the particles from the matrix, the invention
allows the separation to be performed in an automated manner using
conventional laboratory robots.
[0007] It is an object of the present invention to provide a means
to separate solid particles or beads from a liquid matrix.
[0008] It is a further object of the present invention to provide a
means that can be used by automated systems.
[0009] There has thus been outlined, rather broadly, the more
important features of the invention in order that the detailed
description thereof that follows may be better understood, and in
order that the present contribution to the art may be better
appreciated. There are, of course, additional features of the
invention that will be described further hereinafter.
[0010] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of other embodiments and of being practiced or
carried out in various ways. Also, it is to be understood that the
phraseology and terminology employed herein are for the purpose of
description and should not be regarded as limiting.
[0011] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that equivalent
constructions insofar as they do not depart from the spirit and
scope of the present invention, are included in the present
invention.
[0012] For a better understanding of the invention, its operating
advantages and the specific objects attained by its uses, reference
should be had to the accompanying drawings and descriptive matter,
which illustrate preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates an embodiment of the invention as a
pipette tip with round holes and closed bottom.
[0014] FIG. 2 illustrates an embodiment of the invention as a
pipette tip with slotted sides and closed bottom
[0015] FIG. 3 illustrates an embodiment of the invention as a
pipette tip with slotted sides and closed bottom, mounted on a
robotic pipetting system and aspirating a liquid from a vial
containing beads.
DETAILED DESCRIPTION OF THE INVENTION
[0016] A device and methodology is disclosed herein for the
separation of solid particles or beads from a liquid mixture. The
device consists of a new design of disposable pipette tip with
holes or slits in the side Preferably the holes or slits are
smaller than the solid particles or beads from which the liquid is
to be separated. The device is especially suitable for, but not
limited to, use in automated laboratory systems where materials
such as viscous suspensions must be separated from ceramic grinding
beads.
[0017] In a first embodiment, FIG. 1, pipette tip 102 has had the
normal entrance hole blocked 104 and round holes 106 drilled
radially around the tip circumference. In varying embodiments,
pipette tip 102 is plastic and/or disposable.
[0018] In a second embodiment FIG. 2, pipette tip 202 has had the
normal entrance blocked 204 and vertical slits 206 cut radially
around the tip circumference. In varying embodiments, pipette tip
202 is plastic and/or disposable.
[0019] FIG. 3 illustrates a method of use of the second preferred
embodiment, where the pipette tip 202 has been mounted on a robotic
pipettor 304 and plunged into a vial 306 containing a liquid 308
and beads 310 from which the liquid is being separated by
aspiration into the pipette tip at 312.
Description of Experiments Leading to the Preferred Embodiment and
Preferred Methodology
[0020] The task was defined as the aspiration of a viscous
suspension using disposable tips, from a mixture containing
nominally 1 mm diameter zirconia beads. In the first set of
experiments, an easily obtainable and relatively harmless household
scouring agent was used with water to represent a moderately
viscous suspension as the liquid matrix to be separated from the
beads. A Hamilton robot was used for process development and to
demonstrate automation. For these initial experiments a pipette tip
volume of 1000 .mu.l, was used, as this is the size tip available
for use on this robot. Alternate pipette tip volumes are
contemplated.
Method
[0021] A Hamilton Dual Lab Workstation with a 1000 .mu.l pipettor
with disposable tips was used for the first set of experiments.
Around 20 ml of a model suspension consisting of 75% Actiff (an
abrasive cleaning suspension) and 25% water was shaken by hand with
about 5 ml of 1.0 mm diameter zirconia ceramic beads and
subsequently vortexed for 20 seconds on a conventional laboratory
orbital shaker after which the beads settled quickly to the bottom.
The amount of beads was such that a 10 mm layer was present at the
bottom of the vial and the suspension layer extended above this to
a height of 45 mm from the bottom. During each experiment, 25
transfers of liquid, each of 1000 .mu.l were performed to ensure as
much of the 20 ml of suspension used, was transferred.
[0022] Both the method of aspiration and the shape of the tip were
varied. The tips tested included: the normal 1000 .mu.l tip,
various tips with the end cut off at different lengths such that
the opening was maximally 4 mm, a tip with a 3 mm opening on which
a metal wire mesh was affixed, and two tips with the bottom hole
closed off and 4 side holes drilled of 1.2 and 1.0 mm diameter,
respectively (see FIG. 1).
Results of Initial Experiments
[0023] For all tests using the normal tips, beads were transferred.
The beads were either transferred by being aspirated into the
pipette, or were trapped by suction at the entrance to the tip
(which also prevented aspiration of the suspension), and deposited
in the receiver.
[0024] The intent was that, with a larger pipette opening, the
beads could be expelled before transfer. However, even with a 20
sec wait period to allow the beads to settle before expulsion, the
beads had not settled down and could not be expelled from the tip.
This method worked when tested with pure water. When the viscosity
of the liquid is high, complete separation was not possible.
Additionally, in this experiment it was observed that since the tip
was pushed through the bead layer to the bottom of the vial, beads
were being pushed into the tip. Positioning the tip above the bead
layer but in the suspension might prevent beads from being
transferred, though they could still be drawn up from the bottom
and not all the available liquid would be removed from the
vial.
[0025] These pipette tips or methods did not provide a suitable
means to separate the beads from the liquid matrix and alternative
means had to be sought.
[0026] An alternative means was devised to prevent beads from
entering the tip, namely a small copper mesh screen with openings
of 1.about.1.5 mm was placed over a cut-off tip with an opening of
3 mm diameter. Even though this reduced the amount of beads being
transferred significantly from the number using the conventional
pipette tips, several beads were still transferred. Additionally,
manufacture of such a tip would not be economic.
Experiments using the First Embodiment
[0027] In an additional set of experiments, new designs of tip were
tested representing examples of the preferred embodiments, each
with the normal entrance hole blocked; one with four 1.0 mm holes
radially drilled at right angles to the tip axis, 7 mm from the
pipette opening and, similarly, another with 1.2 mm holes drilled
radially at heights of 4, 7 and 10 mm from the end. Each tip was
tested for the transfer of 20 ml of suspension in four consecutive
runs (each of 25 aspiration/dispense cycles determined by the 1000
.mu.l tip volume).
Results Obtained using the First Embodiment
[0028] Only for one transfer, were beads transferred (one bead
only), using the tip with 1.2 mm holes. As the beads themselves
have a nominal diameter of 1.0 mm was determined that one of the
smaller beads was aspired through the hole. Reducing the whole
diameter to 1.0 mm showed no beads being transferred in 4
consecutive separation experiments. It was concluded that the
diameter of the holes should be smaller than any of the beads
present in the formulation.
Experiments using the Second Preferred Embodiment
[0029] Finally, examples of a second embodiment was prepared, using
tips of large volume (5 ml) which were modified by blocking the
normal entrance hole and creating two slots of about 0.8 mm in the
sides of the pipette. These were tested using a manual pipettor on
formulations of agricultural suspensions that had been comminuted
using a bead mill that used beads of the same diameter and
composition as in the previous experiments.
Results Obtained using the Second Preferred Embodiment
[0030] This method required slow and controlled aspiration, due to
the viscous nature of the formulation. Greater control of
aspiration afforded by a robot was demonstrated in the earlier
experiments.
[0031] Because it is intended that these tips would be used in an
automated environment and in cases where the volume of sample in
the vial may vary, the aspiration was tested at different heights
in the vial, namely, above the beads in the suspension phase and
plunged through the beads to the bottom.
[0032] In all cases, the tips provided a means to completely
separate the formulation from the beads. There was no advantage in
terms of separation in plunging the tip though the beads to the
bottom of the vial and almost as much formulation could be
extracted by holding the tip just at the level of the top of the
bead layer. However, in an automated system, the height of this
position may not be known or the volume of the liquid processed may
be small and in these cases, aspiration from the bottom may be
necessary.
Conclusions
[0033] Testing a number of styles of tips has shown that the two
embodiments of the invention that use side-holes with hole
diameters preferably smaller than the bead diameter or with slits
which are preferably narrower than the bead diameter, can be used
to cleanly separate and transfer a liquid including a viscous
suspension from one vial to another, without transfer of the beads.
Additionally, this was demonstrated in an automated system.
[0034] It is concluded that a means to separate beads from a liquid
formulation has been found. Methods have been devised that allow
the means to be applied manually or in an automated
environment.
[0035] Having now described a few embodiments of the invention, it
should be apparent to those skilled in the art that the foregoing
is merely illustrative and not limiting, having been presented by
way of example only. Numerous modifications and other embodiments
are within the scope of one of ordinary skill in the art and are
contemplated as falling within the scope of the invention and any
equivalent thereto. It can be appreciated that variations to the
present invention would be readily apparent to those skilled in the
art, and the present invention is intended to include those
alternatives. Further, since numerous modifications will readily
occur to those skilled in the art, it is not desired to limit the
invention to the exact construction and operation illustrated and
described, and accordingly, all suitable modifications and
equivalents may be resorted to, falling within the scope of the
invention.
* * * * *